Hydraulic Pilot Flow Switching for Low-Load Valve Stability
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Solution Overview
Problem
Existing hydraulic systems in work vehicles face inefficiencies due to high energy consumption and instability in valve dynamics when handling lower hydraulic loads, leading to increased noise, vibration, and heat generation.
Innovation Solution
A system and method that incorporates pilot selector valves to selectively control the source of pilot flow to compensator valves, balancing pressure drops across flow control and compensator valves, reducing energy consumption while enhancing stability for lower hydraulic loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the pump discharges hydraulic fluid at high pressure to compensate for pressure drops across valves, then the hydraulic load can be actuated, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts the pump discharge pressure to match the actual hydraulic load requirements. The controller monitors pilot pressure and flow control valve position to determine when high pressure is needed, versus when lower pressure suffices, thereby reducing unnecessary energy consumption while maintaining adequate power delivery.
Solution Approach 2:
The patent replaces the traditional purely mechanical pressure compensation system with a hybrid system that uses electronic sensors, a controller, and solenoid-operated pilot valves. This substitution allows for more precise and adaptive pressure control, enabling the system to reduce pump pressure when full compensation is not needed, thus lowering energy consumption.
2Use of energy by moving object
If lower hydraulic loads are used to reduce energy consumption, then fuel economy improves, but valve stability decreases leading to increased noise and vibration
Solution Approach 1:
The system introduces a pilot pressure system as an intermediary control mechanism. The pilot pressure, controlled by the controller and pilot valves, acts as a mediator to maintain stable valve operation even when main hydraulic loads are low. This pilot pressure ensures that flow control valves operate smoothly without excessive vibration or noise, while still allowing the main system to run at lower energy consumption levels.
Solution Approach 2:
The system dynamically adjusts pilot pressure levels based on actual operating conditions. The controller monitors system state and modulates pilot valve positions to maintain optimal valve stability across varying load conditions. This dynamic adjustment allows the system to preserve valve stability during low-load operation without requiring continuously high pump pressure, thus maintaining fuel economy.
3Use of energy by moving object
If pilot flow is supplied from downstream of the flow control valve, then energy consumption is reduced, but valve control stability deteriorates for lower hydraulic loads
Solution Approach 1:
The system dynamically selects the pilot flow source based on operating conditions. The controller monitors hydraulic load levels and automatically switches between upstream and downstream pilot flow sources. During low-load conditions, it selects upstream sourcing to maintain valve stability; during high-load conditions, it switches to downstream sourcing to reduce energy consumption, thus adapting to varying operational requirements.
Solution Approach 2:
The system changes the pilot pressure parameter based on system state. By monitoring load conditions and adjusting pilot pressure sourcing accordingly, the system maintains adequate valve control stability when needed while allowing energy reduction when possible. This parameter adjustment resolves the contradiction between energy efficiency and control reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves reduced energy consumption and increased valve stability by distributing pressure drops across both valves, minimizing noise, vibration, and heat generation, particularly for lower hydraulic loads.
Implementation Method 1
a pilot-operated compensator valve fluidly coupled to the fluid supply conduit upstream of the flow control valve... configured to balance pressure drops across both the flow control valve and the compensator valve
Data Source
AI summary
A system for controlling hydraulic fluid flow within a work vehicle includes a hydraulic load and a pump configured to supply hydraulic fluid to the hydraulic load via a fluid supply conduit. The system also includes a flow control valve fluidly coupled to the fluid supply conduit upstream of the hydraulic load, a pilot-operated compensator valve fluidly coupled to the fluid supply conduit upstream of the flow control valve, and a pilot conduit fluidly coupled to the pilot-operated compensator valve such that the pilot conduit is configured to supply a pilot flow of hydraulic fluid to the pilot-operated compensator valve. Additionally, the system include a pilot selector valve configured to selectively fluidly couple the pilot conduit to either a first pilot source conduit or a second pilot source conduit to adjust a source of the pilot flow supplied to the pilot-operated compensator valve.